CLCN3 and Blindness: Studies (18,35) using expression data in adult brain tissue from the dorsolateral prefrontal cortex of the CMC (35) showed that genetic variants encoding CLCN3 are upregulated by schizophrenia risk allele. CLCN3 is a brain-expressed chloride ion channel, implicated in controlling fast excitatory glutamatergic transmission (65). CLCN3−/− mice show neurological symptoms such as blindness, motor coordination deficits and spontaneous hyperlocomotion as well progressive degeneration of the retina, hippocampus and ileal mucosa (66).